QR generated by FoxBarcodeQR doesn't contain the full content

[Rajesh Karunakaran]

Dear friends,

I'm using the community library FoxBarcodeQR for generating qr codes.
Using the below commands

loQr = CREATEOBJECT("FoxBarcodeQR")
s=REPLICATE('X',950)+'...'
lcQRImage = loQr.QRBarcodeImage(s, lpath + "qrimage5.png", 5, 2)

But the result qr code when scanned doesn't show the full 953 characters.

 

[Chris Miller]

I think there is an upper limit of what can be encoded into what size of QR image, specifically what number of QR squares. I think some of the parameters are about the size. If you already used the largest size then you're asking for too much. A finite size always can only encode a finite number of bytes or characters, obviously. I'd also try with something like REPLICATE('1234567890',95)+'abc', for easier verification of the scan result.

Edit: Looking at https://github.com/VFPX/FoxBarcodeQR you can go up from 5 for 165x165 to 12 for 396x396.
Documentation speaks of more than 255 characters - which it does, obviously, because that was a limitation of an earlier version. It doesn't mean the upper limit is now unrestricted, but it doesn't provide information about the upper limits. I guess it varies with the necessary number of bits and the bits used for correction bits and so the correction level.

 

[Rajesh Karunakaran]

This is actually for an e-Invoice. The qr data is base64 encoded and is JWT. The sample qr code has 953 characters and that's why I am testing with a 953 characters string. I am scanning with my mobile phone's qr scanner. When scanning the sample one, I can see the full content. When I generate qr of my data for qr with the library, the result qr when scanned shows truncated data. I tried with all sizes but truncates the same way. I think, there is something, maybe a setting, that I'm missing.

 

[Rajesh Karunakaran]

Chriss, I am using an older version it seems.
I have the new version 2.10. Let me try that.

Will update status here.

 

[Rajesh Karunakaran]

[SOLVED]

Chriss,
The new version gives the complete content.
I guess, the old version was not supporting above 255 characters

Thanks for your support

 

[Chris Miller]

Just as sidenote: In case the QR code can't encode the data you plan to encode, you can always encode a URL that points to the data that's too large to encode, so storing JWTs in a db and retriving them by www.yourdomain.in/jwts/?id=qrcode could work with far smaller QR codes, too. if the QR code only encodes the lookup id(entifier) and even with only 255 bytes allows 2^2048 different JSON web tokens.